Low-profile battery construct with engineered interfaces

ABSTRACT

A battery structure includes an anode packaging material having a first textured surface and an anode metal formed on the first textured surface. A separator is formed on the anode metal. A cathode packaging material includes a second textured surface. A cathode metal is formed on the second textured surface. An active cathode paste is formed on the cathode metal and brought into contact with the separator such that any gap is filled with electrolyte.

BACKGROUND

Technical Field

The present invention relates to battery structures, and moreparticularly to batteries and methods for fabrication that includeengineered interface surfaces to enable higher performance in batterystructures.

Description of the Related Art

Low-profile batteries are employed in many applications. In particularlyuseful applications, low-profile batteries are employed in portableelectronic devices, such as watches or smaller devices, and in manycases much smaller. Many layers in the battery structures are formed byconventional deposition processes. These battery structures includesmooth interfaces between layers. The smooth interfaces may often leadto issues such as poor adhesion of seed metal to package materials,delamination of metal layers from seed metals, high stresses in metallayers and poor wetting or coating on metal layers by hydrogel or othermaterials (e.g., MnO2 pastes to cathodes) in the battery structure. Thepoor wetting or coating and smooth interfaces may also contribute tohigh electrical resistance between layers in the battery structure.

SUMMARY

A battery structure includes an anode packaging material having a firsttextured surface and an anode metal formed on the first texturedsurface. A separator is formed on the anode metal. A cathode packagingmaterial includes a second textured surface. A cathode metal is formedon the second textured surface. An active cathode paste is formed on thecathode metal and brought into contact with the separator such that anygap is filled with electrolyte.

A battery structure includes an active battery region includes atextured anode metal formed on first textured packaging material; ahydrogel separator formed on the textured anode metal. A texturedcathode metal is formed on second textured packaging material, and aMnO₂ paste is formed on the textured cathode metal. A first battery sealregion is configured to contain the hydrogel separator outside theactive battery region on an anode side. A second battery seal region isconfigured to contain the MnO₂ paste outside the active battery regionon a cathode side. An electrolyte is disposed in any gap between thehydrogel separator and the MnO₂ paste, the gap being filled withelectrolyte.

A method for forming a battery structure includes texturing an anodepackaging material to form a first textured surface; depositing one ormore metal layers including an anode metal on the first texturedsurface; forming a separator on the anode metal; texturing a cathodepackaging material to form a second textured surface; depositing acathode metal on the second textured surface; and forming an electrolytebinder paste on the cathode metal, which contacts the separator with anygap being filled with electrolyte.

These and other features and advantages will become apparent from thefollowing detailed description of illustrative embodiments thereof,which is to be read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The disclosure will provide details in the following description ofpreferred embodiments with reference to the following figures wherein:

FIG. 1 is a cross-sectional view of a battery structure havingengineered surfaces in accordance with the present principles;

FIG. 2 is a cross-sectional view of a magnified region of an anodeactive area of the battery structure of FIG. 1 showing engineeredsurfaces in accordance with the present principles;

FIG. 3 is a cross-sectional view of a magnified region of a cathodeactive area of the battery structure of FIG. 1 showing engineeredsurfaces in accordance with the present principles;

FIG. 4 is a cross-sectional view of a magnified region of an anodebattery seal area of the battery structure of FIG. 1 showing engineeredsurfaces in accordance with the present principles;

FIG. 5 is a cross-sectional view of a magnified region of a cathodebattery seal area of the battery structure of FIG. 1 showing engineeredsurfaces in accordance with the present principles;

FIG. 6 is a schematic view of a laser scanning device for formingengineered surfaces in accordance with one embodiment;

FIG. 7 is a graph of discharge capacity of batteries (in μAh) versusweeks showing improved performance for batteries with engineeredsurfaces in accordance with the present principles; and

FIG. 8 is a block/flow diagram showing methods for fabricating a batterystructure having engineered surfaces in accordance with the presentprinciples.

DETAILED DESCRIPTION

In accordance with the present principles, engineered interfaces areemployed between layers of battery structures. The engineered interfacesmay include a number of different technologies and structures. Forexample, for thin film polymer packaging materials (e.g., KAPTON®,polyethylene terephthalate (PET)), a micron level texture may beprovided using rapid laser scanning. Laser scanning also has the effectof annealing stressed metal films, e.g., Zn metal films in the batterystructure. Other embodiments for processing thin polymer films mayinclude techniques such as hot embossing to create texture.

Thin inorganic materials may also be employed as packaging materials.Examples may include thin silicon, thin glass, ceramic, etc. Thesematerials can be laser roughened by picosecond laser scanning, e.g., atwavelengths of 355 nm and/or 266 nm.

In other embodiments, thin silicon may be precision textured by acombination of photolithography and deep reactive ion etching (DRIE)etching. Surface roughening on the order of 0.5 microns peak to valleymay be attained by blanket DRIE without lithography, while texturingwith lithography permits patterns of tens of microns to be etched. Thinglass may be textured by a combination of photolithography and wet HFetching. Mechanical processes may also be employed for surfaceroughening by low cost techniques such as sand-blasting or milling.

The engineered interfaces in an active battery area of the batterystructure provide, e.g., improved adhesion of seed metal to packagematerials, improved adhesion of metal layers (e.g., Zn) to seed metal,low stress metal layer(s) (e.g., laser annealed), good wetting and/orcoating of metal layer by hydrogel and a good interlock of metal oxidepaste to a cathode current collector (providing low electricalresistance). The engineered interfaces in a battery seal area of thebattery structure provide, e.g., improved adhesion of seed metal topackage material and improved adhesion of adhesive to seed metal and/orcurrent collector metal.

It is to be understood that the present invention will be described interms of a given illustrative architecture; however, otherarchitectures, structures, substrate materials and process features andsteps may be varied within the scope of the present invention.

It will also be understood that when an element such as a layer, regionor substrate is referred to as being “on” or “over” another element, itcan be directly on the other element or intervening elements may also bepresent. In contrast, when an element is referred to as being “directlyon” or “directly over” another element, there are no interveningelements present. It will also be understood that when an element isreferred to as being “connected” or “coupled” to another element, it canbe directly connected or coupled to the other element or interveningelements may be present. In contrast, when an element is referred to asbeing “directly connected” or “directly coupled” to another element,there are no intervening elements present.

The present embodiments may include a design for a battery structure foruse with integrated circuits and/or chips. The design may be created ina graphical computer programming language, and stored in a computerstorage medium (such as a disk, tape, physical hard drive, or virtualhard drive such as in a storage access network). If the designer doesnot fabricate batteries, the designer may transmit the resulting designby physical means (e.g., by providing a copy of the storage mediumstoring the design) or electronically (e.g., through the Internet) tosuch entities, directly or indirectly. The stored design is thenconverted into the appropriate format (e.g., GDSII) for the fabricationof battery structures. Photolithographic masks may be utilized to defineareas of a wafer or substrate (and/or the layers thereon) to be etchedor otherwise processed.

Methods as described herein may be used in the fabrication of batterystructures, which may be employed with integrated circuits and/or chips.The chip may be mounted in a single chip package (such as a plasticcarrier, with leads that are affixed to a motherboard or other higherlevel carrier) or in a multichip package (such as a ceramic carrier thathas either or both surface interconnections or buried interconnections).In any case, the chip is then integrated with other chips, discretecircuit elements, and/or other signal processing devices as part ofeither (a) an intermediate product, such as a motherboard, or (b) an endproduct. The end product can be any product that includes integratedcircuit chips, ranging from toys and other low-end applications toadvanced computer products having a display, a keyboard or other inputdevice, and a central processor. The integrated circuits or chips may bepowered using the battery structure.

Reference in the specification to “one embodiment” or “an embodiment” ofthe present principles, as well as other variations thereof, means thata particular feature, structure, characteristic, and so forth describedin connection with the embodiment is included in at least one embodimentof the present principles. Thus, the appearances of the phrase “in oneembodiment” or “in an embodiment”, as well any other variations,appearing in various places throughout the specification are notnecessarily all referring to the same embodiment.

It is to be appreciated that the use of any of the following “/”,“and/or”, and “at least one of”, for example, in the cases of “A/B”, “Aand/or B” and “at least one of A and B”, is intended to encompass theselection of the first listed option (A) only, or the selection of thesecond listed option (B) only, or the selection of both options (A andB). As a further example, in the cases of “A, B, and/or C” and “at leastone of A, B, and C”, such phrasing is intended to encompass theselection of the first listed option (A) only, or the selection of thesecond listed option (B) only, or the selection of the third listedoption (C) only, or the selection of the first and the second listedoptions (A and B) only, or the selection of the first and third listedoptions (A and C) only, or the selection of the second and third listedoptions (B and C) only, or the selection of all three options (A and Band C). This may be extended, as readily apparent by one of ordinaryskill in this and related arts, for as many items listed.

Referring now to the drawings in which like numerals represent the sameor similar elements and initially to FIG. 1, a two-sided batterystructure 10 is shown in accordance with one illustrative embodiment.The battery structure 10 includes an anode 50 and a cathode 52. In oneuseful embodiment, the battery structure 10 is a low-profile structure(e.g., coin cells and smaller) being extremely thin and configured foruse in portable devices. Portable devices may include watches, sensors,very small scale devices, devices that employ coin batteries, etc. Whilethe structure will be described in terms of a particular architectureand materials, it should be understood that changes to the architectureand materials may be made in accordance with the present principles.

The battery structure 10 includes an anode package material 12. Theanode package material 12 may include a thickness of between 1 to 5thousandths of an inch (mils), and preferably about 2 mils. The anodepackage material 12 may include silicon, glass, ceramic, polymer (e.g.,KAPTON®) or other substrate-like material. The anode package material 12is textured in accordance with the present principles. Texturing may beperformed on the anode package material 12 directly and/or after otherlayers have been added to the anode package material 12.

One or more metal layers (e.g., layers 14, 16, 18) may be deposited onthe anode package material 12 to form the anode 50. The one or morelayers may include a seed layer 14. The seed layer 14 may include Ti,although other metals may be employed. The seed layer 14 may include athickness of about 1000 to 5000 Angstroms, and may be formed by asputtering process or other suitable deposition process. The seed layer14 may include an additional seed layer 16. The additional seed layer 16is provided to bond to the seed layer 14 and provide a more uniformplatform for plating a metal layer 20 for the anode 50. The additionalseed layer 16 may include Ni, although other metals may be employed. Theseed layer 16 may include a thickness of about 4500 to 5500 Angstromsand may be formed by a sputtering process or other suitable depositionprocess.

A transition layer 18 may include a plated metal layer, such as Ni(formed on the additional seed layer 16 (e.g., Ni)). The transitionlayer 18 may be formed by an electroless plating or electroplatingprocess, although other suitable deposition processes may be employed.The transition layer 18 may include a thickness of about 0.8 to about1.2 microns. An anode metal layer 20 is formed on the transition layer18 and may include a plated metal layer, such as Zn. The anode metallayer 20 may be formed by an electroless plating or electroplatingprocess, although other suitable deposition processes may be employed.The anode metal layer 20 may include a thickness of about 9.5 to about10.5 microns. The anode metal layer 20 may be directly textured. In oneembodiment, the anode metal layer 20 may be laser scanned to texture thesurface and to anneal the anode metal layer 20 to relieve stress/strainin the anode metal layer 20.

The battery structure 10 includes an active battery region 28 disposedwithin a battery seal area or areas 26. The active battery region 28provides ion transfer to provide charge flow for operation of thebattery structure 10. The seal areas 26 seal materials in the activeregion 28.

On the anode side (50), the active region 28 includes a hydrogelseparator 34. The hydrogel separator 34 includes a water permeablematerial (but physically impermeable) between the anode side (50) andthe cathode side (52) of the battery structure 10. The separator 34keeps the two electrodes apart to prevent electrical shorts whilepermitting the transport of ionic charge carriers and water, which areneeded to close the circuit during the passage of current in the batterystructure 10. The separator 34 may include a polymeric membrane 36forming a microporous layer (e.g., fibers, fabric, etc.). The separator34 and its polymeric membrane 36 permit electrolytes in solution 48 totransport charge carriers.

The separator 34 may include hydrogel that is confined using batteryseal materials. The battery seal materials may include adhesive layers18 and 24 that support a polymer core 22. The adhesive layers 18, 24 mayinclude acrylic or epoxy materials. The polymer core 22 may includepolyethylene terephthalate (PET).

The cathode 52 includes a cathode package material 32. The cathodepackage material 32 may include a thickness of between 1 to 5thousandths of an inch (mils), and preferably about 2 mils. The cathodepackage material 32 may include silicon, glass, ceramic, polymer (e.g.,KAPTON®) or other substrate-like material. The cathode package material32 may be textured in accordance with the present principles. Texturingmay be performed on the cathode package material 32 directly and/orafter other layers have been added to the cathode package material 32.

One or more metal layers may be deposited on the cathode packagematerial 32 to form the cathode 52. The one or more layers may include ametal layer 30. The metal layer 30 may include Ti, although other metalsmay be employed. The metal layer 30 may include a thickness of about4500 to 5500 Angstroms and may be formed by a sputtering process orother suitable deposition process. The metal layer 30 follows thetexture of the cathode package material 32. The metal layer 30 forms acathode current collector. In one embodiment, the metal layer 30 may belaser scanned to texture the surface and to anneal the metal layer 30 torelieve stress/strain in the metal layer 30.

The battery structure 10 includes the active battery region 28 disposedwithin the battery seal area or areas 26. The active battery region 28provides ion transfer to provide charge flow for operation of thebattery structure 10. The seal areas 26 seal materials in the activeregion 28.

On the cathode side (52), the active region 28 includes a paste 38. Thepaste 38 includes an active material, such as, MnO₂ as well as acarbon-based conductor such as graphite or carbon black, although othermaterials may be employed. The paste 38 may be contained by a polymericmembrane 36 forming a microporous layer (e.g., fibers, fabric, etc.),and by battery seal materials. The battery seal materials may includeadhesive layers 18 and 24 that support a polymer core 22. The adhesivelayers 18, 24 may include acrylic or epoxy materials. The polymer core22 may include PET.

The cathode side 52 and anode side 50 are disposed apart initially, andare then brought together with an electrolyte 36 being added to bothsides, such that the wetted cathode paste 38, and the wetted separator34 come into contact at midplane and minimize any gap. The gap can befilled with electrolyte solution 48, if needed.

FIGS. 2-5 show magnified views of regions 40, 42, 44 and 46 in FIG. 1.Regions 40, 42, 44 and 46 indicate texturing of the multiple layers ofthe battery structure 10.

Referring to FIG. 2, region 40 is shown for an anode side of an activebattery region. The anode package material 12, one or more layers 14,16, transition layer 18 and anode metal layer 20 are shown with texturedinterfaces 60. The anode package material 12 may be textured using alaser scan, mechanical scraping, patterned etching, or other process toform ridges, fins, sinusoidal shapes, etc. The textured surfaces 60 mayinclude two or three-dimensional shapes to increase surface area and/orroughness between adjoining materials.

In one embodiment, the textured surface on the anode package material 12may be carried through the metal layers 14, 16 and/or 18 by conformallycoating the metal layers 14, 16 and/or 18 on the textured surface ofanode package material 12. Then, the metal layer 20 may be formed andtextured by similar methods. In one embodiment, the metal layer 20 istextured using a laser scanning process. The laser scanning process mayinclude heating the metal layer 20 to provide an anneal to relievestress/strain of the metal layer 20. In other embodiments, any or all ofthe layers may be textured independently. The hydrogel of the separator34 is shown engaging one of the textured surfaces of the metal layer 20.

The textured surfaces provide good adhesion of seed metal 14 to thepackage material 12, prevent metal delamination of the metal layer 20and/or transition layer 18 from seed metal(s) 14, 16 and reduce stressin the metal layer 20. Poor wetting/coating of the metal layer 20 byhydrogel of the separator 34 is overcome by the texturing in accordancewith the present embodiment.

Referring to FIG. 3, region 42 is shown for a cathode side of an activebattery region. The cathode package material 32, one or more layers 30and cathode paste 38 are shown with textured interfaces 62. The cathodepackage material 32 may be textured using a laser scan, mechanicalscraping, patterned etching or other process to form ridges, fins,sinusoidal shapes, etc. The textured surfaces 62 may include two orthree-dimensional shapes to increase surface area and/or roughnessbetween adjoining materials.

In one embodiment, the textured surface on the cathode package material32 may be carried through the metal layer(s) 30 by conformally coatingthe metal layer 30 on the textured surface of the cathode packagematerial 32. Then, the metal layer 30 may be formed and textured bysimilar methods. In one embodiment, the metal layer 30 is textured usinga laser scanning process. The laser scanning process may include heatingthe metal layer 30 to provide an anneal to relieve stress/strain in themetal layer 30. In other embodiments, any or all of the layers may betextured independently. The paste is shown engaging the textured surfaceof the metal layer 30.

The textured surfaces provide interlocking between the paste 38 and themetal layer 30 (e.g., cathode current collector). This improves/reduceselectrical resistance.

Referring to FIG. 4, region 44 is shown for an anode side of a batteryseal region. The anode package material 12, one or more layers 14, 16,transition layer 18 and anode metal layer 20 are shown with texturedinterfaces 60. The textured surfaces 60 may include two orthree-dimensional shapes to increase surface area and/or roughnessbetween adjoining materials.

In one embodiment, the textured surface on the anode package material 12may be carried through the metal layers 14, 16 and/or 18 by conformallycoating the metal layers 14, 16 and/or 18 on the textured surface ofanode package material 12. Then, the metal layer 20 may be formed andtextured by similar methods. In one embodiment, the metal layer 20 istextured using a laser scanning process. In other embodiments, any orall of the layers may be textured independently. The textured surfacesprovide good adhesion of seed metal 14 to the package material 12 andprevent metal delamination of the metal layer 20 and/or transition layer18 from seed metal(s) 14, 16. The metal layer 20 may interface with theseal materials 24 using a textured surface or a smooth interface 64. Thetextured surface is made with the hydrogel of the separator 34 toovercome issues as described herein.

Referring to FIG. 5, region 46 is shown for a cathode side of a batteryseal region. The cathode package material 32, one or more layers 30 andseal materials 24 are shown with textured interfaces 62. The cathodepackage material 32 may be textured using a laser scan, mechanicalscraping, patterned etching, or other process to form ridges, fins,sinusoidal shapes, etc. The textured surfaces 62 may include two orthree-dimensional shapes to increase surface area and/or roughnessbetween adjoining materials.

In one embodiment, the textured surface on the cathode package material32 may be carried through the metal layer(s) 30 by conformally coatingthe metal layer 30 on the textured surface of the cathode packagematerial 32. In one embodiment, the metal layer 30 is textured using alaser scanning process. The laser scanning process may include heatingthe metal layer 30 to provide an anneal to relieve stress/strain of themetal layer 30. In other embodiments, any or all of the layers may betextured independently. The metal layer 30 may interface to the sealmaterials 24 using a textured interface 66.

Referring to FIG. 6, a laser scanning setup 100 is illustratively shownfor surface engineering interfaces in accordance with one illustrativeembodiment. A laser scanner 102 is arranged over a workpiece 104. Theworkpiece 104 includes a portion of the battery structure 10 that is tobe textured to provide improvements in accordance with the presentprinciples. The scanner 102 includes the ability to move a laser spot110 in the x and y directions relative to the workpiece 104, a platformwith the workpiece 104 on it moves relative to the spot 110. In oneembodiment, the scanner 102 operates with an F-theta scan lens 106.Example parameters for the scanner 102 include 1 meter/sec serpentinescan with a 15 micron (full width at half maximum (FWHM)) spot size anda 15 micron line/line pitch. The laser may include 1 to 2 Watts powerwith a 50 kHz repetition rate. These parameters are illustrative asother parameters may be employed in accordance with the presentprinciples.

A top view 112 of the workpiece 104 illustratively shows a scan path 114that creates micron level roughness in polymers such as KAPTON®, PET,plated metal Zn, etc. in accordance with the present principles.

Referring to FIG. 7, a graph of discharge capacity (μAh) versus numberof weeks of storage is shown to compare battery structures with laserengineered interfaces in accordance with the present principles, againstbattery structures with smooth interfaces (conventional). A plot 202shows battery structures with laser engineered interfaces. A plot 204shows battery structures with smooth interfaces (conventional).

Two batches of 48 batteries each were created using KAPTON® packagingand PET/acrylic tape seals. One batch made use of laser engineering oninterfaces as shown in FIGS. 2-5 while the other batch has smoothinterfaces. Every week, four of each batch were discharged and plottedin plot 202 and 204, respectively. Average discharge capacity wasdecided higher for the laser engineered samples in plot 202 over plot204.

Referring to FIG. 8, a method for forming a battery structure isillustratively shown in accordance with exemplary embodiments. In somealternative implementations, the functions noted in the blocks may occurout of the order noted in the figures. For example, two blocks shown insuccession may, in fact, be executed substantially concurrently, or theblocks may sometimes be executed in the reverse order, depending uponthe functionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

In block 302, an anode packaging material is textured to form a firsttextured surface. Texturing the anode packaging material may includelaser writing, lithographical patterning, mechanically embossingtextural elements, etc. Thin organic or inorganic materials may also beemployed as packaging materials. The texturing may include laserroughened surfaces by, e.g., picosecond laser scanning at wavelengthsof, e.g., 355 nm and/or 266 nm. In other embodiments, texturing may beperformed by photolithography and etching, e.g., (DRIE) etching or wetetching (HF etch). Surface roughening on the order of 0.5 microns peakto valley may be attained by blanket DRIE without lithography, whiletexturing with lithography permits patterns of tens of microns to beetched. Thin glass may be textured by a combination of photolithographyand wet HF etching. Mechanical processes may also be employed fortexturing/surface roughening by sand-blasting, embossing, milling, etc.

In block 304, one or more metal layers are deposited to form an anode.The deposition may include one or more seed layers formed on the anodepackaging material wherein the anode metal is formed on the seed layer.The seed layers or layers provide a surface for applying or plating ananode metal. A transition layer may be formed on the seed layer whereinthe anode metal is formed on the transition layer. The seed layers maybe sputtered while the transition layer and the anode metal may beplated to reduce cost. The seed layers and transitional layers may beconformally deposited or formed to maintain the textured surface of theanode packaging material. The anode metal is formed on the firsttextured surface of the anode packaging material to increase contactsurfaces and improve battery performance.

In block 305, the anode metal may be textured independently. In oneembodiment, a laser scanning to form a roughened or textured surface maybe employed that also anneals the anode metal to reduce stress/strain.

In block 306, a separator is formed on the anode metal. The separatormay include hydrogel and a porous membrane for electrolyte transfer. Theseparator is sealed outside an active battery area using adhesivesand/or a core polymer. The battery seal area need not be textured butmay also benefit from having textured surfaces.

In block 308, a cathode packaging material is textured to form a secondtextured surface. Texturing the cathode packaging material may includelaser writing, lithographical patterning, mechanically embossingtextural elements, etc. Thin organic or inorganic materials may also beemployed as packaging materials. The texturing may include laserroughened surfaces by, e.g., picosecond laser scanning at wavelengthsof, e.g., 355 nm and/or 266 nm. In other embodiments, texturing may beperformed by photolithography and etching, e.g., (DRIE) etching or wetetching (HF etch). Surface roughening on the order of 0.5 microns peakto valley may be attained by blanket DRIE without lithography, whiletexturing with lithography permits patterns of tens of microns to beetched. Thin glass and other materials may be textured by a combinationof photolithography and wet HF etching. Mechanical processes may also beemployed for texturing/surface roughening by sand-blasting, embossing,milling, etc.

In block 310, a cathode current collector metal is deposited on thesecond textured surface. The cathode current collector metal layer(s)may be conformally deposited or formed to maintain the textured surfaceof the cathode packaging material. In block 312, a paste, e.g., a blendof MnO₂ and graphite) may be formed on the cathode current collectormetal. The paste may be sealed outside the active battery area usingadhesives and/or a core polymer. The battery seal area need not betextured but may also benefit from having textured surfaces. A gapformed between the separator and the paste is to be minimized. Any gapmay be filled with an electrolytic material (solution). The separatorsaturated with electrolyte and should push right up against the cathodepaste. This gives best performance. If a gap does exist, it is filledwith electrolyte.

The textured surface formed in accordance with the present principlesmay include two or three dimensional shapes such as hills and valleys,pyramids, sinusoidal shapes, grooves, wavy trenches, roughed surfaces,etc. In particularly useful embodiments, the shapes may includelaser-written grooves. It should be noted that the battery structure mayinclude one textured surface (e.g., a layer in the anode only) or anynumber of textured surfaces (layers in the anode and cathode). Thetextures surface may be formed over a portion of the surface or may beintermittently formed on a surface or surfaces.

In block 314, processing continues to complete the battery structure,which may include enclosing the battery or installing the battery withinanother assembly. The battery structure may be employed as a low-profilebattery to be employed in an electronic device, such as a watch,stand-alone sensor, a biomedical device, etc.

Having described preferred embodiments for a low-profile batteryconstruct with engineered interfaces (which are intended to beillustrative and not limiting), it is noted that modifications andvariations can be made by persons skilled in the art in light of theabove teachings. It is therefore to be understood that changes may bemade in the particular embodiments disclosed which are within the scopeof the invention as outlined by the appended claims. Having thusdescribed aspects of the invention, with the details and particularityrequired by the patent laws, what is claimed and desired protected byLetters Patent is set forth in the appended claims.

What is claims is:
 1. A battery structure, comprising: an anodepackaging material having a first textured surface; anode metalconformally formed on the first textured surface such that the anodemetal completely fills any gaps between protrusions on the firsttextured surface, and having a first textured interface on a sideopposite the first textured surface; a separator formed on the anodemetal; a cathode packaging material having a second textured surface; acathode metal formed on the second textured surface; and an activecathode paste formed on the cathode metal and brought into contact withthe separator such that any gap is filled with an electrolyte.
 2. Thebattery structure as recited in claim 1, wherein the separator includeshydrogel.
 3. The battery structure as recited in claim 1, wherein atleast one of the first textured surface and the second textured surfaceincludes three dimensional shapes.
 4. The battery structure as recitedin claim 1, wherein at least one of the first textured surface and thesecond textured surface include laser-written grooves.
 5. The batterystructure as recited in claim 1, further comprising a seed layer formedon the anode packaging material wherein the anode metal is formed overthe seed layer.
 6. The battery structure as recited in claim 5, furthercomprising a transition layer formed on the seed layer wherein the anodemetal is formed on the transition layer.
 7. The battery structure asrecited in claim 1, wherein the first textured surface includes atexture pattern and layers of metal are conformally formed on thetexture pattern between the anode packaging material and the anode metalto provide a second textured interface for the anode metal that followsthe first textured surface.
 8. The battery structure as recited in claim1, wherein the second textured surface includes a texture pattern andthe cathode metal is conformally formed on the texture pattern toprovide a textured interface on an opposite side of the cathode metalfrom the second textured surface.
 9. A battery structure, comprising: anactive battery region including: a textured anode metal formed on afirst textured packaging material; a hydrogel separator formed on thetextured anode metal; a textured cathode metal formed on a secondtextured packaging material; a MnO₂ paste formed on the textured cathodemetal; and a first battery seal region configured to contain thehydrogel separator outside the active battery region on an anode side; asecond battery seal region configured to contain the MnO₂ paste betweenthe first battery seal region and the second battery seal region on acathode side; and an electrolyte disposed in any gap between thehydrogel separator and the MnO₂ paste, the gap being filled withelectrolyte.
 10. The battery structure as recited in claim 9, whereinthe textured anode metal includes three dimensional shapes.
 11. Thebattery structure as recited in claim 9, wherein the textured anodemetal includes laser-written grooves.
 12. The battery structure asrecited in claim 9, wherein the textured cathode metal includes threedimensional shapes.
 13. The battery structure as recited in claim 9,wherein the first textured packaging material and the second texturedpackaging material include laser-written grooves.
 14. The batterystructure as recited in claim 9, further comprising: a seed layer formedbetween the anode metal and the first textured packaging material; and atransition layer formed on the seed layer wherein the anode metal isformed on the transition layer.
 15. The battery structure as recited inclaim 9, wherein the first textured packaging material includes atexture pattern and layers of metal are conformally formed on thetexture pattern between the anode packaging material and the anode metalto provide a textured interface for the anode metal that follows thefirst textured surface.
 16. The battery structure as recited in claim 9,wherein the second textured packaging material includes a texturepattern and the cathode metal is conformally formed on the texturepattern to provide a textured interface on an opposite side of thecathode metal from the texture pattern.
 17. A battery structure,comprising: an anode packaging material having a first textured surface;anode metal formed on the first textured surface wherein a thickness ofthe anode metal is greater than a texture depth of the first texturedsurface such that the anode metal completely fills any gaps betweenprotrusions on the first textured surface, and wherein the anode metalis further textured at an interface with the separator; a separatorformed on the anode metal; a cathode packaging material having a secondtextured surface; a cathode metal formed on the second textured surface;and an active cathode paste formed on the cathode metal and brought intocontact with the separator such that any gap is filled with anelectrolyte.
 18. The battery structure as recited in claim 17, whereinat least one of the first textured surface and the second texturedsurface includes three dimensional shapes.
 19. The battery structure asrecited in claim 18, further comprising a seed layer formed on the anodepackaging material and a transition layer formed on the seed layerwherein the anode metal is formed on the transition layer.